In the smartphone industry, the quality of display image is getting more and more important. Since the smartphone is carried by end users anytime and anywhere, the quality of display image under various ambient light conditions is one of key points to make differentiation for devices.
Old or low cost mobile phones usually don't have any way to detect difference of ambient light conditions. In this case, the device has only 1 set of display tuning parameters which is intended to cover all the possible conditions. The way to improve the image quality is to tune the parameters optimized against the worst condition.
However, this way of optimization causes bad side effects: worse image quality in other conditions, increase of power consumption, increase of noise emission, etc.
In order to solve the problem pointed out, recently many smartphone has the capability of automatic control of display brightness. For example, the basic principle is: firstly, detect ambient brightness (illuminance in scientific word); secondly, calculate suitable display brightness; thirdly, change the display brightness.
However, the applicant found that the prior art has following major problem: it cannot control color or white balance dynamically such that the quality of display image is still not good in some conditions.